ARTICLES 435 



'73), Jordan ('82), A. Geikie ('83), Seler ('84), Vetter ('84), 

 Lapparent ('8$), Perrier ('87), Caullery ('00), May ('02), Giraud 

 '02), and Seurat ('06) make no mention of the structural 

 eatures here under consideration ; similar discussions by Lang- 

 :nbeck ('90) and Lendenfeld ('02) take some account of em- 

 Dayments, but are silent as to unconformable contacts. 



As above stated, Walther's description of the reefs of Sinai 

 peninsula is exceptional in making explicit mention of the 

 anconformable reef contacts with tilted and eroded strata ('88) ; 

 squally exceptional are Vaughan's statements in several recent 

 articles, to the effect that unconformities exist between reef 

 limestones and their foundations in Florida and the West 

 Indies, and Foye's description of unconformable reefs in Fiji 

 ('17). However, in the nearly thirty years between Walther's 

 early report and these later studies, a number of geologists 

 conducting structural investigations in the East Indies, without 

 special regard to coral reefs, have recognised the unconformable 

 contact between elevated reefs and their foundations, as has 

 already been briefly noted. 



In view of the prevailing silence as to embayments and 

 unconformities among observers of coral reefs, it is perhaps 

 not unnatural that the authors of text-books on geology and 

 physical geography should say nothing as to the occurrence 

 of these important structural features of fringing, barrier, and 

 elevated reefs ; though it does seem strange that they should 

 not call attention to the theoretical value of such features in 

 the discussion of competing theories, inasmuch as both em- 

 bayments and unconformities are easily shown by deduction 

 to be essential consequences of Darwin's theory, and to be 

 impossible consequences of all coral-reef theories which postu- 

 late a constant relation of land and sea level. 



Yet, as a matter of fact, with the three exceptions noted 

 below, neither the observational occurrence nor the theoretical 

 expectation of these features is mentioned in the chapters or 

 paragraphs devoted to coral reefs in Lyell's Principles of Geology 

 (1872), Peschel-Leipoldt's Physische Erdkunde (1879), Hann, 

 Hochstetter, and Pokorny's Allgemeine Erdkunde ( 1 881 ), Green's 

 Physical Geology (1882), Hahn's Inselstudien (1883), Giinther's 

 Lehrbuch der Geophysik (1885), Phillip's Manual of Geology 

 (1885), Neumayr's Erdgeschichte (1886), Prestwich's Geology 

 (1886), Richtofen's Fiihrer fur Forschungsreisende (1886), Suess' 



